Question: Is there a test to determine what vitamins and/or minerals are deficient in our bodies? This would be for the purpose of only taking what's really needed.

There are laboratory tests for many different nutrients, but each of these would have to be ordered individually by your health care provider. It’s probably easier to consult with a dietitian after keeping a food intake record for several weeks to get an idea of overall nutrient intake for starters. An experienced health care provider would probably also be looking for any visual signs of nutrient deficiencies. Individual library or Internet research for any particular medical condition and associated nutrient deficiencies might further help to narrow the field of specific concerns. You would need to discuss individual concerns with your health care provider, so that he/she could order the appropriate tests for specific nutrients of concern.